THE ELECTROTHERMAL THE ELECTROTHERMAL ANALYSIS OF A SWITCHED ANALYSIS OF A SWITCHED MODE VOLTAGE REGULATOR MODE VOLTAGE REGULATOR Krzysztof Górecki and Janusz Krzysztof Górecki and Janusz Zarębski Zarębski Department of Marine Department of Marine Electronics Electronics Gdynia Maritime University, Gdynia Maritime University, POLAND POLAND D E P A R T M E N T F M A R I N E E LE C T R O N I C
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THE ELECTROTHERMAL ANALYSIS OF A SWITCHED MODE VOLTAGE REGULATOR Krzysztof Górecki and Janusz Zarębski Department of Marine Electronics Gdynia Maritime.
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THE ELECTROTHERMAL THE ELECTROTHERMAL ANALYSIS OF A SWITCHED ANALYSIS OF A SWITCHED
MODE VOLTAGE REGULATORMODE VOLTAGE REGULATOR Krzysztof Górecki and Janusz ZarębskiKrzysztof Górecki and Janusz Zarębski
Department of Marine Electronics Department of Marine Electronics
The changes in description of the error amplifier block
In the model all terminals of IC, selfheating, nonlinear characteristics of semiconductor devices are taken into account
77
The The ETMsETMs of the diode of the diode and the MOSFET and the MOSFET
• The general conceptionThe general conception
+ ++ +
• Only characteristics of the forward biased diode and switched-on transistor operating in SMPS are important
Electrothermal hybrid model
SPICEisothermal
built-in model
Controlled sources modelling the
influence of selfheating
Thermal model
88
The The ETMsETMs of the diode of the diode and the MOSFET and the MOSFET (cont.)(cont.)
0TTRSiE jRSRS 01 TTE ju iupth
0TTRDiE jRDDRD
0TTE juG
DDSth iup
0
0,5
1
1,5
2
2,5
3
3,5
4
0 0,1 0,2 0,3 0,4 0,5 0,6
u [V]
i [A
]
1N5822
0
2
4
6
8
10
0 0,25 0,5 0,75 1 1,25 1,5 1,75 2
uDS [V]
i D [
A]
IRF640
uGS = 12 VTa = 300 K
99
Results of calculations Results of calculations and measurementsand measurements
Transient analysis till the steady-stateTransient analysis till the steady-stateOne non-physical thermal time constant – to short the time of One non-physical thermal time constant – to short the time of calculationscalculations
COMP
VFB
ISENSE
RT/CT GND
OUT
VCC
VREFU
UC
384
2
1
2
3
4 5
6
7
8L
RoCo
D1
M1
RS
Vin
+Vcc
C1
D2
R2
R3
C3D3
CT
R4
Q1
RT
R5R6
R7
R8
C4
R10
R9
P1
P2
R11
C5
1
1
2
2
Vout
BOOST converter
1010
Results - opened feedback loopResults - opened feedback loop
ConclusionsConclusions The presented calculations and measurements results confirm the
correctness of the proposed by the authors electrothermal model of the controller UC3842 and the hybrid electrothermal models of the MOS transistor and of the diode.
The calculations and measurements results show the influence of both the input signals of the controller and the values of the boost converter elements on the output voltage.
The possibility of taking into account the phenomenon of selfheating enabled, among others, determining from the computer simulations the admissible values of load resistance and the regulator input voltage, at which the voltage regulator operates properly and the admissible temperature of its component elements is not exceeded.